The Basics of Four-Stroke Engines

Total Page:16

File Type:pdf, Size:1020Kb

The Basics of Four-Stroke Engines Youth Explore Trades Skills Automotive Service Technician The Basics of Four-Stroke Engines Description Students will be introduced to basic engine parts, theory and terminology. Understanding how an engine works and knowing some key related parts and terminology is important for working on any vehicle. The information is broken down into three major sections: “Basic Engine Parts,” “Basic Engine Terminology” and “Basic Four-Stroke Cycle Engine Theory.“ Lesson Outcomes The student will be able to: • Identify and explain the function of basic engine parts • Identify and explain basic engine terminology • Identify the four piston strokes of a four-stroke cycle engine • Describe the action and function of each piston stroke Assumptions • The students will have little or no prior knowledge of how engines work, terminology or parts. • The teacher is familiar with the information being taught. Note: This information is given as a guide to the minimum amount of material to be covered for a basic understanding of the engine and how it works. Much more can be added as the instructor sees fit. Terminology Valve train: all the parts that are used to open and close valves. This may include parts such as valve springs, keepers, lifters, cam followers, shims, rockers and push rods. Any other terminology used will be explained as required during the activities. Estimated time 90–120 minutes (including a question and answer session) Recommended number of students 20, based on the BC Technology Educators’ Best Practice Guide Facilities A classroom, computer lab or workshop with tables and chairs sufficient for 20 students. This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License unless otherwise indicated. The Basics of Four-Stroke Engines Automotive Service Technician Materials • Basic engine parts to show as examples, or images of them. A wide variety would be best (1, 4, 6 and 8 cylinders) • Engine cutaway Resources Four Stroke Engine Animation of four-stroke engine in motion. Other depicted engines can be found on the home page. www.animatedengines.com/otto.html Automobile Engine: Introduction https://auto.howstuffworks.com/engine1.htm How Car Engines Work www.howstuffworks.com/engine.htm World’s Largest and Most Powerful Diesel Engine General interest—description of the largest two-stroke diesel engine, designed for use in container ships. http://wonderfulengineering.com/worlds-largest-and-most-powerful-diesel-engine/ Print Resources Stockel, Martin. Auto Mechanics Fundamentals. Goodheart-Wilcox Co., 1990. McGraw-Hill Education (author). Automotive Excellence, Volume 1 (3rd Edition). Glencoe/ McGraw-Hill, 2006. 2 Youth Explore Trades Skills Automotive Service Technician The Basics of Four-Stroke Engines Activity This information can be presented in many different ways and formats: straight theory lessons, worksheets, computer research assignments or textbook assignments. This information is meant only to be the essential basics to build a foundation on how an engine functions. 1. Basic Engine Parts Engine Block The engine block is the foundation and centre of the engine. Blocks come in many different sizes, shapes and styles. The engine block holds the cylinder, the crankshaft, connecting rods (“con rods”) and pistons. The large round holes in the block, called cylinders, are where the pistons slide up and down. Figure 1—Cylinder block with head attached Youth Explore Trades Skills 3 The Basics of Four-Stroke Engines Automotive Service Technician Piston A piston slides up and down a cylinder and pushes the crankshaft around. The piston connects to the crankshaft via the connecting rods. Figure 2—Piston Figure 3—Piston with connecting rod attached Piston Rings Each piston has two compression rings and one oil control ring to help seal the piston in the cylinder. First compression ring groove Second compression ring groove Oil control ring groove Skirt Figure 4—A piston with two compression rings and one oil control ring Figure 5—Piston rings (compression rings and oil control ring, left to right) 4 Youth Explore Trades Skills Automotive Service Technician The Basics of Four-Stroke Engines Connecting Rods Connecting rods connect the pistons to the crank. They utilize an I-beam construction for strength. Figure 6—Connecting rod Crankshaft The crankshaft is bolted to the bottom of the engine block through bearings so it can rotate freely. It is sometimes referred to as the crank. The crankshaft converts the vertical motion of the pistons and connecting rods to rotational motion. One end of the crankshaft is connected to a flywheel that transfers the engine power to the wheels through a transmission (manual or automatic). Figure 7—Crankshaft with pistons and connecting rods Figure 8—Crankshaft of a 1-cylinder engine with attached connecting rod attached Youth Explore Trades Skills 5 The Basics of Four-Stroke Engines Automotive Service Technician Cylinder Head The cylinder head is bolted to the top of the cylinder block. It serves as a cover for the cylinders and pistons. The cylinder head helps to create the top part of the combustion chamber. An engine “breathes” through the cylinder head. It lets an air/gas mixture into the engine and exhaust out of the engine. The valves and valve train control the breathing of the engine by opening and closing the valves at the appropriate time. Figure 9—Top view of cylinder head with camshafts attached Figure 10—Bottom view of cylinder head showing where the valves sit Note: This has four valves per cylinder (two intake and two exhaust). 6 Youth Explore Trades Skills Automotive Service Technician The Basics of Four-Stroke Engines Figure 11—Cylinder head being attached to engine block Valves Valves can be divided into two groups: • Intake valves control the flow of the air/gas mixture into the engine. • Exhaust valves control the flow of exhaust out of the engine. Figure 12—Exhaust and intake valves Figure 13—Valve Youth Explore Trades Skills 7 The Basics of Four-Stroke Engines Automotive Service Technician Camshaft The camshaft controls the opening and closing of the valves. There is one lobe on the camshaft for each valve in the engine. Camshaft lobe design dictates three things: • How far the valve opens • How fast the valve opens • How long the valve opens Depending on the engine type, the camshaft can be located either in the engine block or over the head (OHC) or double OHC (DOHC). Figure 14—Cam lobe profile showing the opening and closing angles Figure 15—Camshaft 8 Youth Explore Trades Skills Automotive Service Technician The Basics of Four-Stroke Engines Figure 16—In-the-block camshaft Figure 17—Camshaft located over the head Lifters (Tapetts) Lifters are the link between the cam and valves. They are so named because they actually lift as the cam lobe rotates and open the valves. There are two basic types of lifters: • The hydraulic lifter • The solid lifter Youth Explore Trades Skills 9 The Basics of Four-Stroke Engines Automotive Service Technician Timing Chain/Belt/Gears These parts are used in different combinations and configurations to connect the crankshaft to the camshaft. They keep the valves’ opening and closing timed with the piston movement. Timing belts should be replaced every 100,000 km or every five years. Valve Train The valve train includes all the parts that are used to open and close valves. This may include parts like valve springs, keepers, lifters, cam followers, shims, rockers and push rods. Figure 18—Diagram of an engine with overhead camshafts, demonstrating valve train components Flywheel The flywheel attaches to the crankshaft, and uses its momentum to power the engine through the three non-power strokes (intake, compression and exhaust). Because an 8-cylinder car has more power strokes than a 4-cylinder car, the flywheel will be smaller and lighter as there is less need for the momentum carry capabilities. • Flywheels are used in standard transmissions. • Flexplates are used in automatic transmissions. Flywheels and flexplates have a ring gear for the starter. 10 Youth Explore Trades Skills Automotive Service Technician The Basics of Four-Stroke Engines 2. Basic Engine Terminology Bore: the distance across the cylinder (or the diameter). Bottom dead centre (BDC): the lowest point in the cylinder that the piston reaches. Combustion chamber: the space left at the top of the cylinder when the piston is at top dead centre (TDC). This also includes any space in the cylinder head. Compression: the squishing or squeezing of the air/fuel mixture from BDC to TDC. The more the mixture is compressed, the more power it can produce. Compression ratio: the difference as expressed through a ratio of the space left in the cylinder when the piston is at TDC versus BDC. For example, 8:1 means that the space when the piston is at BDC is 8 times bigger than when the piston is at TDC. Cubic inch displacement (CID): the engine size. For example, Chevy 350 (cubic inches), Mustang 5.0 (cubic litres) or Honda 1800 cc (cubic centimetres). Even though 5.0 L and 1800 cc are metric measurements, they are often referred to as the CID of an engine. CID is a mathematical calculation that takes into account the bore and stroke of the cylinder times the number of cylinders in the engine. It basically measures how much volume or air a cylinder can displace or push out from BDC to TDC. Engine types: engines can be classified in many different ways, but three basic engine types likely to be encountered in an automotive shop are: • Four-stroke cycle engine—takes four stokes of the piston to complete a cycle • Two-stroke cycle engine—takes two strokes of the piston to complete a cycle • Diesel—(two or four stroke) uses heat of compression rather than a spark plug to ignite the fuel that is directly injected into the cylinder Each of these engines can come in several different configurations.
Recommended publications
  • Engine Components and Filters: Damage Profiles, Probable Causes and Prevention
    ENGINE COMPONENTS AND FILTERS: DAMAGE PROFILES, PROBABLE CAUSES AND PREVENTION Technical Information AFTERMARKET Contents 1 Introduction 5 2 General topics 6 2.1 Engine wear caused by contamination 6 2.2 Fuel flooding 8 2.3 Hydraulic lock 10 2.4 Increased oil consumption 12 3 Top of the piston and piston ring belt 14 3.1 Hole burned through the top of the piston in gasoline and diesel engines 14 3.2 Melting at the top of the piston and the top land of a gasoline engine 16 3.3 Melting at the top of the piston and the top land of a diesel engine 18 3.4 Broken piston ring lands 20 3.5 Valve impacts at the top of the piston and piston hammering at the cylinder head 22 3.6 Cracks in the top of the piston 24 4 Piston skirt 26 4.1 Piston seizure on the thrust and opposite side (piston skirt area only) 26 4.2 Piston seizure on one side of the piston skirt 27 4.3 Diagonal piston seizure next to the pin bore 28 4.4 Asymmetrical wear pattern on the piston skirt 30 4.5 Piston seizure in the lower piston skirt area only 31 4.6 Heavy wear at the piston skirt with a rough, matte surface 32 4.7 Wear marks on one side of the piston skirt 33 5 Support – piston pin bushing 34 5.1 Seizure in the pin bore 34 5.2 Cratered piston wall in the pin boss area 35 6 Piston rings 36 6.1 Piston rings with burn marks and seizure marks on the 36 piston skirt 6.2 Damage to the ring belt due to fractured piston rings 37 6.3 Heavy wear of the piston ring grooves and piston rings 38 6.4 Heavy radial wear of the piston rings 39 7 Cylinder liners 40 7.1 Pitting on the outer
    [Show full text]
  • Harrop Camshaft Grind Specifications
    Harrop Engineering Australia Pty Ltd www.harrop.com.au ABN: 87 134 196 080 Phone: +61 3 9474 - 0900 96 Bell Street, Preston, Fax: +61 3 9474 – 0999 Melbourne, VIC, 3072, Australia Email: [email protected] Harrop Camshaft Grind Specifications Harrop HO1 Camshaft 226/232 .607”/.602” @ 112 LSA Great NA camshaft Lumpy idle but acceptable driveability, Great power and torque Manual or auto standard gear ratios are ok but 3.7 or 3.9 would be preferred. Automatic may require stall converter. Could be used in boosted application but due to low LSA Would require smaller pulley to be increase boost. Harrop HO2 camshaft 224/232 .610” / .610” @ 114 LSA Great blower camshaft offering acceptably lumpy idle and great drivability, this camshaft will give great power through the mid to high RPM range. As this camshaft is more aggressive then the H05. Normally this would require a stall converter, it can be run on a standard converter but it may push on it slightly. Sound clip: https://www.youtube.com/watch?v=NvOGohRd7-k Harrop H03 Camshaft 232/233 .610” / .602” @ 112 LSA Will give great lumpy cammed affect, Low LSA would take boost out of a forced induction motor. Largest recommend camshaft for a 5.7 N/A , Acceptable in 6.0L and 6.2L square port engines, Must have 3.7 (square port) or 3.9 (LS1) for the best results in a manual car. Auto would require stall converter. 1 / 2 File: Harrop Letter Head “Commercial in Confidence” Issue:12th January 2018 designdevelop deliver Print: Friday, 25 September 2020 ` Harrop HO4 camshaft 234/238 .593” / .595” @ 114 LSA The H04 is designed with Forced induction in mind but can be used as a naturally aspirated camshaft as well.
    [Show full text]
  • Small Engine Parts and Operation
    1 Small Engine Parts and Operation INTRODUCTION The small engines used in lawn mowers, garden tractors, chain saws, and other such machines are called internal combustion engines. In an internal combustion engine, fuel is burned inside the engine to produce power. The internal combustion engine produces mechanical energy directly by burning fuel. In contrast, in an external combustion engine, fuel is burned outside the engine. A steam engine and boiler is an example of an external combustion engine. The boiler burns fuel to produce steam, and the steam is used to power the engine. An external combustion engine, therefore, gets its power indirectly from a burning fuel. In this course, you’ll only be learning about small internal combustion engines. A “small engine” is generally defined as an engine that pro- duces less than 25 horsepower. In this study unit, we’ll look at the parts of a small gasoline engine and learn how these parts contribute to overall engine operation. A small engine is a lot simpler in design and function than the larger automobile engine. However, there are still a number of parts and systems that you must know about in order to understand how a small engine works. The most important things to remember are the four stages of engine operation. Memorize these four stages well, and everything else we talk about will fall right into place. Therefore, because the four stages of operation are so important, we’ll start our discussion with a quick review of them. We’ll also talk about the parts of an engine and how they fit into the four stages of operation.
    [Show full text]
  • SV470-SV620 Service Manual
    SV470-SV620 Service Manual IMPORTANT: Read all safety precautions and instructions carefully before operating equipment. Refer to operating instruction of equipment that this engine powers. Ensure engine is stopped and level before performing any maintenance or service. 2 Safety 3 Maintenance 5 Specifi cations 13 Tools and Aids 16 Troubleshooting 20 Air Cleaner/Intake 21 Fuel System 31 Governor System 33 Lubrication System 35 Electrical System 44 Starter System 47 Emission Compliant Systems 50 Disassembly/Inspection and Service 63 Reassembly 20 690 01 Rev. F KohlerEngines.com 1 Safety SAFETY PRECAUTIONS WARNING: A hazard that could result in death, serious injury, or substantial property damage. CAUTION: A hazard that could result in minor personal injury or property damage. NOTE: is used to notify people of important installation, operation, or maintenance information. WARNING WARNING CAUTION Explosive Fuel can cause Accidental Starts can Electrical Shock can fi res and severe burns. cause severe injury or cause injury. Do not fi ll fuel tank while death. Do not touch wires while engine is hot or running. Disconnect and ground engine is running. Gasoline is extremely fl ammable spark plug lead(s) before and its vapors can explode if servicing. CAUTION ignited. Store gasoline only in approved containers, in well Before working on engine or Damaging Crankshaft ventilated, unoccupied buildings, equipment, disable engine as and Flywheel can cause away from sparks or fl ames. follows: 1) Disconnect spark plug personal injury. Spilled fuel could ignite if it comes lead(s). 2) Disconnect negative (–) in contact with hot parts or sparks battery cable from battery.
    [Show full text]
  • The Starting System Includes the Battery, Starter Motor, Solenoid, Ignition Switch and in Some Cases, a Starter Relay
    UNIT II STARTING SYSTEM &CHARGING SYSTEM The starting system: The starting system includes the battery, starter motor, solenoid, ignition switch and in some cases, a starter relay. An inhibitor or a neutral safety switch is included in the starting system circuit to prevent the vehicle from being started while in gear. When the ignition key is turned to the start position, current flows and energizes the starter's solenoid coil. The energized coil becomes an electromagnet which pulls the plunger into the coil. The plunger closes a set of contacts which allow high current to reach the starter motor. The charging system: The charging system consists of an alternator (generator), drive belt, battery, voltage regulator and the associated wiring. The charging system, like the starting system is a series circuit with the battery wired in parallel. After the engine is started and running, the alternator takes over as the source of power and the battery then becomes part of the load on the charging system. The alternator, which is driven by the belt, consists of a rotating coil of laminated wire called the rotor. Surrounding the rotor are more coils of laminated wire that remain stationary (called stator) just inside the alternator case. When current is passed through the rotor via the slip rings and brushes, the rotor becomes a rotating magnet having a magnetic field. When a magnetic field passes through a conductor (the stator), alternating current (A/C) is generated. This A/C current is rectified, turned into direct current (D/C), by the diodes located within the alternator.
    [Show full text]
  • Overview of Materials Used for the Basic Elements of Hydraulic Actuators and Sealing Systems and Their Surfaces Modification Methods
    materials Review Overview of Materials Used for the Basic Elements of Hydraulic Actuators and Sealing Systems and Their Surfaces Modification Methods Justyna Skowro ´nska* , Andrzej Kosucki and Łukasz Stawi ´nski Institute of Machine Tools and Production Engineering, Lodz University of Technology, ul. Stefanowskiego 1/15, 90-924 Lodz, Poland; [email protected] (A.K.); [email protected] (Ł.S.) * Correspondence: [email protected] Abstract: The article is an overview of various materials used in power hydraulics for basic hydraulic actuators components such as cylinders, cylinder caps, pistons, piston rods, glands, and sealing systems. The aim of this review is to systematize the state of the art in the field of materials and surface modification methods used in the production of actuators. The paper discusses the requirements for the elements of actuators and analyzes the existing literature in terms of appearing failures and damages. The most frequently applied materials used in power hydraulics are described, and various surface modifications of the discussed elements, which are aimed at improving the operating parameters of actuators, are presented. The most frequently used materials for actuators elements are iron alloys. However, due to rising ecological requirements, there is a tendency to looking for modern replacements to obtain the same or even better mechanical or tribological parameters. Sealing systems are manufactured mainly from thermoplastic or elastomeric polymers, which are characterized by Citation: Skowro´nska,J.; Kosucki, low friction and ensure the best possible interaction of seals with the cooperating element. In the A.; Stawi´nski,Ł. Overview of field of surface modification, among others, the issue of chromium plating of piston rods has been Materials Used for the Basic Elements discussed, which, due, to the toxicity of hexavalent chromium, should be replaced by other methods of Hydraulic Actuators and Sealing of improving surface properties.
    [Show full text]
  • The Achates Power Opposed-Piston Two-Stroke Engine
    Gratis copy for Gerhard Regner Copyright 2011 SAE International E-mailing, copying and internet posting are prohibited Downloaded Wednesday, August 31, 2011 08:49:32 PM The Achates Power Opposed-Piston Two-Stroke 2011-01-2221 Published Engine: Performance and Emissions Results in a 09/13/2011 Medium-Duty Application Gerhard Regner, Randy E. Herold, Michael H. Wahl, Eric Dion, Fabien Redon, David Johnson, Brian J. Callahan and Shauna McIntyre Achates Power Inc Copyright © 2011 SAE International doi:10.4271/2011-01-2221 technical challenges related to emissions, fuel efficiency, cost ABSTRACT and durability - to name a few - and these challenges have Historically, the opposed-piston two-stroke diesel engine set been more easily met by four-stroke engines, as demonstrated combined records for fuel efficiency and power density that by their widespread use. However, the limited availability of have yet to be met by any other engine type. In the latter half fossil fuels and the corresponding rise in fuel cost has led to a of the twentieth century, the advent of modern emissions re-examination of the fundamental limits of fuel efficiency in regulations stopped the wide-spread development of two- internal combustion (IC) engines, and opposed-piston stroke engine for on-highway use. At Achates Power, modern engines, with their inherent thermodynamic advantage, have analytical tools, materials, and engineering methods have emerged as a promising alternative. This paper discusses the been applied to the development process of an opposed- potential of opposed-piston two-stroke engines in light of piston two-stroke engine, resulting in an engine design that today's market and regulatory requirements, the methodology has demonstrated a 15.5% fuel consumption improvement used by Achates Power in applying state-of-the-art tools and compared to a state-of-the-art 2010 medium-duty diesel methods to the opposed-piston two-stroke engine engine at similar engine-out emissions levels.
    [Show full text]
  • From Crank to Click the Evolution of the Car Key in 1769, the French
    Car Key Origins: From Crank to Click The Evolution of the Car Key In 1769, the French inventor, Nicolas-Joseph Cugnot, introduced the first automobile to the world. Ever since then, cars have continued to evolve at a remarkable rate. You might think that car keys have accompanied cars all along, but that's a little inaccurate. Car keys, along with auto locksmith services, only saw the light of day in the late 1940's. So what's the story of cars and keys? Read on to find out. Early Cars Had no Keys This might come as a shock, but older cars had no keys to speak of. In the early years of the last century, many used to chain their vehicles to lampposts in order to secure them. Back in the day as well, to start your car's engine, you needed to manually crank up the engine. But this had its drawbacks. With engines getting bigger and more powerful, rotating a lever to start your car proved inconvenient, even dangerous. In turn, this made way for the electric starter, a small motor driven with a high enough voltage to start the engine. A Step closer to a Car Key In addition to the electric starter, the early decades of the twentieth century featured others types of starters, such as spring motors and air starter motors. The driver was able to operate those starters by pressing a button on the dashboard or the floor. Alternatively, a few cars had pedals to engage the starter by foot. The advent of button-operated starters meant an easier, safer way of starting your car.
    [Show full text]
  • The Trilobe Engine Project Greensteam
    The Trilobe Engine Project Greensteam Michael DeLessio 4/19/2020 – 8/31/2020 Table of Contents Introduction ................................................................................................................................................... 2 The Trilobe Engine ................................................................................................................................... 2 Computer Design Model ............................................................................................................................... 3 Research Topics and Design Challenges ...................................................................................................... 4 Two Stroke Engines .................................................................................................................................. 4 The Trilobe Cam ....................................................................................................................................... 5 The Flywheel ............................................................................................................................................ 6 Other “Tri” Cams ...................................................................................................................................... 7 The Tristar ............................................................................................................................................. 8 The Asymmetrical Trilobe ...................................................................................................................
    [Show full text]
  • Understanding Overhead-Valve Engines Once Unheard of These Engines Now Supply the Power for Nearly All of Your Equipment
    Understanding Overhead-Valve Engines Once unheard of these engines now supply the power for nearly all of your equipment. By ROBERT SOKOL Intertec Publishing Corp., Technical Manuals Division You've all heard about overhead valves when shopping Valve-Design Characteristics for power equipment, but what do they mean to you? Do The valves consist of a round head, a stem and a groove you need overhead valves? Do they cost more? What will at the top of the valve. The head of the valve is the larger they do for you? Twenty years ago, overhead valves were end that opens and closes the passageway to and from the unheard of in any type of power equipment. Nowadays, it combustion chamber. The stem guides the valve up and is difficult to find a small engine without them. down and supports the valve spring. The groove at the top In an engine with overhead valves, the intake and of the valve stem holds the valve spring in place with a exhaust valve(s) is located in the cylinder head, as opposed retainer lock. The valves must open and close for the air- to being mounted in the engine block. Many of the larger and-fuel mix to enter, then exit, the combustion chamber. engine manufacturers still offer "standard" engines that Proper timing of the opening and closing of the valves is have the valves in the block. Their "deluxe" engines have required for the engine to run smoothly. The camshaft con- overhead valves and stronger construction. Overhead trols valve sequence and timing.
    [Show full text]
  • Poppet Valve
    POPPET VALVE A poppet valve is a valve consisting of a hole, usually round or oval, and a tapered plug, usually a disk shape on the end of a shaft also called a valve stem. The shaft guides the plug portion by sliding through a valve guide. In most applications a pressure differential helps to seal the valve and in some applications also open it. Other types Presta and Schrader valves used on tires are examples of poppet valves. The Presta valve has no spring and relies on a pressure differential for opening and closing while being inflated. Uses Poppet valves are used in most piston engines to open and close the intake and exhaust ports. Poppet valves are also used in many industrial process from controlling the flow of rocket fuel to controlling the flow of milk[[1]]. The poppet valve was also used in a limited fashion in steam engines, particularly steam locomotives. Most steam locomotives used slide valves or piston valves, but these designs, although mechanically simpler and very rugged, were significantly less efficient than the poppet valve. A number of designs of locomotive poppet valve system were tried, the most popular being the Italian Caprotti valve gear[[2]], the British Caprotti valve gear[[3]] (an improvement of the Italian one), the German Lentz rotary-cam valve gear, and two American versions by Franklin, their oscillating-cam valve gear and rotary-cam valve gear. They were used with some success, but they were less ruggedly reliable than traditional valve gear and did not see widespread adoption. In internal combustion engine poppet valve The valve is usually a flat disk of metal with a long rod known as the valve stem out one end.
    [Show full text]
  • Swampʼs Diesel Performance Tips to Help Remove and Install Power
    Injectors-Chips-Clutches-Transmissions-Turbos-Engines-Fuel Systems Swampʼs Diesel Performance Competition Parts For Your Diesel 304-A Sand Hill Rd. La Vergne, TN 37086 Tel 615-793-5573 or (866) 595-8724/ Fax 615-793-5572 Email: [email protected] Tips to help remove and install Power Stroke injectors. Removal: After removing the valve covers and the valve cover gaskets, but before removing any injectors, drain the oil rails by removing the drain plugs inside the valve cover. On 94-97 trucks theyʼre just under where the electrical connectors are on the gasket. These plugs are very tight; give them a sharp blow with a hammer and punch to help break them loose, then use a 1/8" Allen wrench. The oil will drain out into the valve train area and from there into the crankcase. Donʼt drop the plugs down the push rod holes! Also remove one of the plugs on top of each oil rail, (beside where the lines from the High Pressure Oil Pump enter) for a vent to allow air to enter so the oil can drain. The plugs are 5/8”. Inspect the plug O-rings and replace if necessary. If the plugs under the covers leak, it will cause a substantial loss of performance. When removing the injectors, oil and fuel from the passages in the cylinder head drains down through the injector bore into the cylinders. If not removed, this can hydro-lock the engine when cranking. There is a ~40cc dish in the center of each piston. Fluid accumulates in it, as well as in the corner on the outside of the piston between the piston top and the cylinder wall, due to the 45* slope of the cylinder bank.
    [Show full text]